Is the current rise in COVID-19 hospitalizations really the result of people moving indoors to enjoy air conditioning? Experts and journalists often make this assumption when they’re quoted in the media about the virus’s small summer “waves” or “surges” (which, this year, is really more like a small uptick). Similarly, when there’s a winter surge, it’s usually attributed to people flocking inside to escape the cold.
But whether it’s summer or winter, the explanation falls flat. Because regardless of the season, humans are generally an indoor species. And the virus is still evolving new ways to get around our immunity, most recently spinning off a new omicron subvariant called EG.5.
While there’s good evidence that the virus spreads more easily indoors, there’s very little evidence that people are spending much more time indoors now than they were in the spring. Nor is there much evidence that most people ever spend enough time outside to affect the global ebb and flow of SARS-CoV2 or other respiratory viruses.
People live 90 percent of their lives indoors, said Joseph Allen, director of the healthy buildings program at Harvard School of Public Health. He’d like to see more emphasis on ventilation and filtration of indoor air to protect people from wildfire smoke and pollutants as well as viruses.
On an individual level, it’s true that people are less likely to contract a virus at a park or beach than at a crowded indoor party. But on a societal level, attributing surges in virus to people moving indoors doesn’t make much sense. So what actually causes viral diseases to wash over us in waves or in seasonal peaks?
Michael Osterholm, an epidemiologist at Center for Infectious Disease Research and Policy, says there’s more to learn about the ecology of viruses — how they interact with each other and with our immune systems. He wishes doctors and journalists would stop using the term “tripledemic” to describe the co-existence of flu, RSV and COVID in late 2022. COVID-19 was on the way out, and the other diseases weren’t worse than usual but simply peaked early.
Another new COVID variant might emerge any time, and the current variant, omicron, continues to spin off new subvariants. Osterholm said he is still studying the impact of these new variants, which are on the rise around the world and became dominant in the U.S. this week.
The rise in cases highlights an uncomfortable reality: We don’t — and have never had — complete control over the pandemic, even though we do have tools to reduce risk for individuals.
Early in the pandemic there was a popular notion that we’re failing a group project, the goal of which would be to conquer the virus. But ending the pandemic before the vaccines were available wasn’t realistic, and the experts led people in too many directions — not all of them helpful. Many people stayed home, disinfecting mail and groceries while railing against beachgoers and images of Swedish people in outdoor cafes. Much of that effort and the outrage was misplaced and not anchored by anything like scientific evidence.
Now that airborne transmission is well understood, people can reduce the risk to elderly friends and relatives by holding weddings and other big gatherings outdoors. People can also reduce their risk of contracting or transmitting COVID-19 (and a lot of other viruses) by wearing a tight-fitting, high-quality mask, staying home if they feel ill and washing their hands a lot. And of course, vaccines can reduce the risk of an illness becoming serious. Booster shots can be important for those at high risk.
Scientists should keep searching for an evidence-based explanation for the rise and fall of virus waves, large and small. It’s an intriguing question and the answer could prove useful. Having a clear answer would be a lot more satisfying than admitting we just don’t know.
